按列值对二维数组的行进行分组，并将整行推入分组的子数组中[重复]

Question

我有以下数组：

$comments   = array();
$comments[] = array('member_id' => '17',
                    'time'      => '2011-05-10 11:10:00',
                    'name'      => 'John Smith',
                    'comment'   => 'Test Comment 1');
$comments[] = array('member_id' => '25',
                    'time'      => '2011-05-10 11:26:00',
                    'name'      => 'David Jones',
                    'comment'   => 'Test Comment 2');
$comments[] = array('member_id' => '17',
                    'time'      => '2011-05-10 13:15:00',
                    'name'      => 'John Smith',
                    'comment'   => 'Test Comment 3');

我该如何按

member_id

对其进行分组？这样我就可以使用以下格式在页面上显示评论：

约翰·史密斯（2条评论）

• 2011-05-10 11:10:00 |测试评论1
• 2011-05-10 13:15:00 |测试评论3

大卫·琼斯（1 条评论）

• 2011-05-10 11:26:00 |测试评论2

Answer 1

一种解决方案是按名称字段对它们进行排序（请查看 usort），但更简单的方法可能是通过这种方式填充一个新数组：

$grouped = array();
foreach($comments as $c) {
  if(!isset($grouped[$c['name']]) {
    $grouped[$c['name']] = array();
  }

  $grouped[$c['name']][] = $c;
}

//Now it's just a matter of a double foreach to print them out:
foreach($grouped as $name => $group) {
  //print header here
  echo $name, "<br>\n";

  foreach($group as $c) {
    //print each comment here
  }
}

Answer 2

我建议使用第二个分组数组

$groups[] = array();
foreach( $comment as $k=>$v ) {
    $groups[$v['member_id']][] = $k
}

然后打印

foreach( $group as $m_id=>$arr ) {
    echo "Group $m_id<br/>\n";
    foreach( $arr as $k ) {
        echo $comment[$k]."<br/>\n";
    }
}

Answer 3

您应该尝试采用多维数组。

 $comment_groups[] = array();
    $m_id = '';

    foreach( $comment_groups as $key=>$val ) {
         if($key == 'member_id'){
             $m_id = $val;
            }
           $comment_groups[$m_id]][] = $val;
   }

然后就可以按照你想要的显示方式打印了。